The possibility that mercury may be released from dental amalgam restorations and absorbed in the body is of concern to scientists and dental practitioners as well as the general public. Although dental amalgam restorations are believed to present no health hazard to the majority of patients, the advances in sciences and the increased awareness of environmental problems are reasons for a reexamination of the issue. Since some dissolution occurs when most metals are exposed to liquid environments, it is important to know how much mercury dissolves from dental amalgams, what affects the dissolution rate, and how the release can be minimized. In this study the rate of mercury dissolution in synthetic saliva from liquid mercury, individual structural phases existing in dental amalgams, and representative commercial dental amalgams will be measured as a function of the electrode potential; the data will have general significance and will make possible to predict the dissolution rate from different amalgams and minimize it by alloy modification. The form of the dissolved species, which determines the way mercury may enter the body, will be determined. The relative importance of the major components of the environment in the dissolution process will be studied. Electrochemical measurements, Atomic Absorption Spectrophotometry, and Pulse Anodic Stripping Voltammetry will be the principal experimental tools. The dissolution of mercury may be accelerated by the specific conditions of the oral exposure. The effects of temperature, galvanic contacts with other alloys, crevice and oxygen concentration cells, and abrasion will be examined. The results of this study will show how substantial the rate of dissolution may be under various conditions, what types of amalgam release least amounts of mercury, and how the alloys and restorations can be modified to minimize the rate of mercury dissolution.